Gene Therapy for Hemophilia Moves Ahead
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"We use electricity, a brief electrical pulse, to transfer a piece of DNA that has the factor VIII gene in it into cells that are [taken] from the patient," he says. "We do this in the laboratory, and it's called electroporation."
Specifically, the investigators take a skin sample from people with hemophilia A, and obtain some cells from the sample. Using electroporation, they insert the gene that produces factor VIII into these cells. They then make these altered cells multiply and insert them back into the patients' bodies.
"The method that we are testing is a completely new and novel technology," says Roth. "What this will do, if it is successful, is potentially correct the person's disease such that one would no longer be dependent on [factor VIII] replacement therapy for survival."
Roth and colleagues performed this technique on six men with hemophilia. After one year, they have found that, "everything was safe, and everything was well tolerated. There were only some minor side effects of the implant procedure, like black and blue marks where the surgery was done. But that's a predictable thing that went away. ... There were no [unpredicted] adverse events related to the material or procedure. There were no [immune] reactions to the factor VIII or the [implanted] cells."
Not only does the procedure appear to be safe, early results suggest that it is effective. For a time, the researchers were able to detect factor VIII in the blood of four of the six treated men, and two of these men had fewer bleeds than usual for a few months.
Roth warns, however, that this study was not designed to detect the effectiveness of the new technique, only the safety. "We don't want the community to think we've proven that we've got a new technique out there for them," he says. "What we've proven is that this is safe, well tolerated, and we don't see immune reactions. We think this is something we can proceed with."